-Clinical study Oral lichen planus 
Reticular form oj oral lichen planus. 
A 19-year observatwn perwd 
in 7J patientsfrom Skmenia 
M. Rode, A.A. Kansky and M . Kogoj-Rode 
ABSTRACT 
Background. 75 patients (60 of them women) with the reticular form of oral lichen planus (OLP) were 
under observation during a 19-year period. 
Methods. The patients had no complaints and were referred to the specialist by their dentist. They were 
studied at the Department of Clinical Oral Pathology of the Medical Center in Ljubljana. · 
Results. A remission of the lesions was observed in 24, intensification in 9, while in 42 the lesions 
persisted. During the period of observation no malignant alteration was observed. 
Conclusion. In well-documented cases of the reticular form of OLP the malignant transformation is rare, 
the differential diagnosis Between OLP and leukoplakia may be however difficult on purely clinical ground. 
For this reason a biopsy is suggested in such cases. 
Introduction 
Lichen planus (LP) is a relatively common disorder 
which affects O .5% to 1.9% of population. Approximately 
20% of patients in a referral oral surge1y practice were 
diagnosed with oral lichen planus (OLP) (1,2). 
OLP is a common chronic inflammatory disease of 
the oral mucous membranes .It is observed on the 
buccal mucosa, oral vestibule, gingivae and the tongue. 
It has a variety of clinical appearances: reticular, papular, 
plaque-like, erosive, ulcerative, bullous and atrophic 
(3 ,4,5,6). Reticular OLP is generally characterized by 
lesions consisting of radiating white or grey papules in 
a linear, annular or retiform arrangement, forming typi-
cal reticular patches , rings and streaks on the oral mu-
cosa. The reticular form is the most common ancl is gene-
rally asymptomatic, while the ulcerative ancl bullos 
forms are frequently associatecl with pain. Comparecl 
with skin lesions, nrncosal affections are far more 
chronic in nature, w ith less than 20% unclergoing com-
plete remission (3). 
OLP is histopathologically well clefinecl, characte-
rized by a T cell-clominated infiltrate in proximity to the 
basal celi layer of the epithelium, by epithelial basal 
celi clestruction ancl thickening or clisruption of the base-
ment membrane (7,8,9,10). 
Although the etiology of OLP is very complex and 
tl1e pathological process remains presently obscure (11), 
there are inclications that it may be associatecl with stress, 
some systemic cliseases, drugs ancl immunologic clis-
Acta Dermatoven APA Vol 9, 2000, No 4 - - - --~------ ----- - 137 
Oral lichen planus 
orders (12). Results of numerous investigations indicate 
that cell-mediated mechanisms are involved in the initi-
ation and progression ofthe lesions (13). It is reasonable 
to assume that OLP is a localized autoimmune disease. 
Walsh et al. suggest that modified keratinocyte surface 
antigens are the target for the cytotoxic celi response, 
whereas mast cells, antigen-presenting Langerhans cells 
and cytokines produced by lymphocytes and keratino-
cytes play a key role in the evolving lesion (14). There 
is an accumulating evidence for the role of TNF-a in 
OLP (15). Recent studies suggest the involvement of 
heat shock proteins as autoantigens (15). A number of 
studies suggest that there is a close relationship between 
hepatitis C virus infection and OLP in certain groups of 
patients (16,17) . 
OLP is important since the possibility of malignant 
transformation is mentioned in the literature (18,19,20, 
21,22), the malignant potential is stili questionable. 
Overexpression of the p53 gene in the OLP samples 
without gene mutations were reported. This may be a 
physiological response and may serve to protect against 
mutagenesis; p53 mutation appears to be an early event 
in the process of carcinogenesis (23) . 
There have been a number of mainly retrospective 
studies from severa! countries that show only a minimal 
risk of malignant transformation. In his population-
based 10-1 9 year prospective study Murti et al. (19) 
reported its malignant transformation as 0.3%, Silverman 
et al. (14) reported malignant transformation in 1.2%, 
Holmstrup et al. (22) in 1.5%, Salem (24) in 5.6%, Voute 
et al. (25) in 2.7%, and Silverman et al. (26) a 2.3% rate 
of malignant transformation during a mean tirne of 7.5 
years. 
Material and methods 
Our data on 75 patients are described and compared 
with those from other studies. Clinical data include age, 
gender, previous medica! history, medications, thera-
peutic protocol and malignant association. 
The data on 75 patients with reticular form of oral 
lichen were collected from a previous survey by the 
Department of Clinical Oral Pathology of Medica! Centre 
in Ljubljana. The patients had no complaints and were 
directed to the specialist by their dentist who had disco-
vered the lesions. From ali patients the history of the 
present OLP, as well as general medica! and dental histo-
ries were taken. The patients were studied since 1975 
and were followed through to 1994. The mean age at 
the initial presentation was 58.3 years with a standard 
deviation of 5.1 years. The age range was from 41 to 64 
years. Of the 75 patients 60 (80 %) were women. Three 
investigators double performed the oral examinations 
of all lesions checking each other in daylight and using 
the mouth mirror. Oral reticular lichen was diagnosed 
and registered on a clinical basis . The score of 0-3 was 
138 
Figure 1: Reticular oral lichen planus: typical 
lesions on the buccal mucosa. 
recorded according to the following criteria: 
Score O = no lesions, normal mucosa 
Score 1 = white striae, less than 1 cm2 
Score 2 = white striae, more than 1 cm2 
Score 3 = white striae, more than 2 cm2 . 
Figure 2: Reticulat oral lichen planus: a more 
intense lesion on the buccal mucosa 
Clini c al s tud y 
Acta Dermatoven APA Vol 9, 2000, No 4 
C l i n i c a l s t u d y Oral lichen planus 
Table 1. Lesion sites in 75 patients with oral lichen planus into other forms of OLP was not observed. 
Sites No. 
Buccal mucosa 47 
Retromolare pad 15 
Tongue 10 
Floor of the mouth and gingiva 3 
All lesions 75 
Table 2. Evolution of lesions during a 19-year observation 
-period 
Situation No. 
Remission 24 
Complete remission o 
Intensification 9 
Status guo 42 
All changes 75 
From all our patients biopsies oflesional oral mucosa 
were removed under local anesthesia and fixed in 10% 
formaldehyde solution for routine histopathology. The 
diagnosis of OLP was confirmed histologically at the 
Institute of Pathology, Medica! Faculty of Ljubljana. 
No patient had characteristic skin lesions. Patients 
with lichenoid lesions close to dental amalgam fillings 
and patients w ith oral lichenoid drug eruptions (27) 
were not included in the group under obse1vation . 
The patients were re-examined once every six 
months and lesions showing clinical changes were 
registered. Biopsy was repeated after 10 years of obser-
vation in 9 patients with a progredient OLP. They 
received no treatment during the years under obser-
vation. 
Results 
1. Location of the lesions 
The primary lesion site was the buccal mucosa, with 
secondary sites of the retromolar pads, tertiaty sites on 
the tongue and guaternary sites on the floor of the mouth 
and the gingiva. Multiple lesion sites occurred freguently 
(Table 1). 
2. Lesions' evolution 
Disease remission was noted in 24 patients after initial 
presentation. A more pronounced expression of the 
lesions was noted in 9 patients and an unchanged 
situation was observed in 42 patients over a 19-year 
period after initial observation (Table 2). Transformation 
3. Histopathologic finclings 
Ali tissue specimens showed similar histological abnor-
malities. The epithelium of the oral mucosa was hyper-
plastic with acanthotic projections, hyperplasia was seen 
in the spinous layer; the epithelium was coverecl by a 
parakeratotic layer. Liguefaction of the basal cell layer 
was observed focally, accompanied by marked mono-
nuclear infiltrate at the dermoepiclermal junction. No 
atypia of the epithelial cells was found. Histopatho-
logical findings after 10 years of observations were simi-
lar to previous findings. No clysplasia was founcl. 
4. No malignant alteration was detected in any of the 75 
patients. 
D-iscussion 
The data presentecl are consistent w ith data from 
previous studies with regarcl to location and clisease 
Figure 3: Histopathology of reticular oral lichen 
planus: parakeratosis, acanthosis, vacuolar 
degeneration of basal cells, typical lichenoid 
lymphocytic infiltrate. H.E. x 195. 
Acta Dermatoven APA Vol 9, 2000, No 4 ------------------ 139 
Oral lichen planus 
chronicity (3,14). Disease remission was noted without 
treatment. Female patients prevailed. The routine biopsy 
procedure in the diagnosis of OLP is a controversial one 
(3,28). From all lesions in our study biopsies were 
routinely taken. All tissue specimens showed similar 
histological abnormalities. No atypia of the epithelial 
cells was found. 
We recorded no cases of malignant transformation. 
Our results confirm findings of Brown et al. (3) and do 
not support the observations of Silverman et al. (20) 
who reported malignant transformation in one of the 
cases with reticular OLP. The results of Holmstrup et al. 
(29,30) who reported that reticular OLP is related to oral 
cancer could not be confirmed either. Reticular oral 
lichen planu s manifests itself with typical clinical symp-
toms. There are lesions that clinically do not resemble 
oral lichen planus but have lichenoid features in 
histology, and others that clinically resemble oral lichen 
planus , but show atypia or dysplasia from the onset (26). 
This may be the source of some of the controversy in 
the literature concerning its malignant transformation 
(22), (25). No case of malignant transformation in 75 
patients followed up to 19 years was recorded. We re-
corded disease remission without therapy in 24 patients 
and intensification of mucosal striae in 9 patients. Our 
study does no support the observations of Brown et al. 
(3) or the findings of Thorn et al. (30) who suggested a 
complete remission. 
A malignant transformation of ali forms of oral lichen 
planus cannot be excluded. However, it would therefore 
REFERENCE S 
Figure 4: Same as figure 3. H.E. x 250. 
seem prudent to confirm the clinical diagnosis of OLP 
histologically, and to have patients followed up re-
gularly. 
Conclusion 
It is suggested that a biopsy should be performed in 
ali instances of OLP and that the patients should be 
followed up regularly. 
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AUTHORS' 
ADDRESSES 
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Maljaž Rode DMD, PhD, Projessor oj stomatology, Department oj Oral 
Pathology, Medical Centre, Prvomajska 5, 1000 Ljubljana, Slovenia 
Andrej Kansky DMD; Msc, Department oj Maxillojacial Surgery; 
University Clinical Centre, Zaloška 2, 1525 Ljubljana, Slovenia 
Mirela Kogoj-Rode DMD, PhD, Department oj Stomatolof,y, 
University Glinica! Centre, Zaloška 2, 1525 Ljubljana, Slovenia 
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